Use shared ec2 module snippet in elasticache module

cloud/elasticache

@@ -479,11 +479,11 @@ def main():
             cache_security_groups={'required': False, 'default': ['default'],
                                    'type': 'list'},
             zone={'required': False, 'default': None},
-            aws_secret_key={'default': None,
-                            'aliases': ['ec2_secret_key', 'secret_key'],
+            ec2_secret_key={'default': None,
+                            'aliases': ['aws_secret_key', 'secret_key'],
                             'no_log': True},
-            aws_access_key={'default': None,
-                            'aliases': ['ec2_access_key', 'access_key']},
+            ec2_access_key={'default': None,
+                            'aliases': ['aws_access_key', 'access_key']},
             region={'default': None, 'required': False,
                     'aliases': ['aws_region', 'ec2_region'],
                     'choices': AWS_REGIONS},
@@ -492,9 +492,7 @@ def main():
         )
     )
 
-    aws_secret_key = module.params['aws_secret_key']
-    aws_access_key = module.params['aws_access_key']
-    region = module.params['region']
+    ec2_url, aws_access_key, aws_secret_key, region = get_ec2_creds(module)
 
     name = module.params['name']
     state = module.params['state']
@@ -511,24 +509,6 @@ def main():
     if state == 'present' and not num_nodes:
         module.fail_json(msg="'num_nodes' is a required parameter. Please specify num_nodes > 0")
 
-    if not aws_secret_key:
-        if 'AWS_SECRET_KEY' in os.environ:
-            aws_secret_key = os.environ['AWS_SECRET_KEY']
-        elif 'EC2_SECRET_KEY' in os.environ:
-            aws_secret_key = os.environ['EC2_SECRET_KEY']
-
-    if not aws_access_key:
-        if 'AWS_ACCESS_KEY' in os.environ:
-            aws_access_key = os.environ['AWS_ACCESS_KEY']
-        elif 'EC2_ACCESS_KEY' in os.environ:
-            aws_access_key = os.environ['EC2_ACCESS_KEY']
-
-    if not region:
-        if 'AWS_REGION' in os.environ:
-            region = os.environ['AWS_REGION']
-        elif 'EC2_REGION' in os.environ:
-            region = os.environ['EC2_REGION']
-
     if not region:
         module.fail_json(msg=str("Either region or EC2_REGION environment variable must be set."))
 
@@ -551,7 +531,8 @@ def main():
 
     module.exit_json(**facts_result)
 
-# this is magic, see lib/ansible/module_common.py
-#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
+# import module snippets
+from ansible.module_utils.basic import *
+from ansible.module_utils.ec2 import *
 
 main()